Class B, C and D were given some mini cupcakes to sell for their charity drive. The average number of mini cupcakes the 3 classes had at first was 234. After Class C sold twice as many mini cupcakes as Class B and Class D sold ²₃ as many mini cupcakes as Class C, the average number of mini cupcakes the 3 classes had left was 52. How many mini cupcakes did Class B and Class D sell altogether?

Class B	Class C	Class D
1x3	2x3
	3x2	2x2
3 u	6 u	4 u

Class B : Class C : Class D
3 : 6 : 4

Total number of mini cupcakes that the 3 classes had at first
= 3 x 234
= 702

Number of mini cupcakes that the 3 classes left
= 3 x 52 
= 156

Number of mini cupcakes that were sold by 3 classes
= 702 - 156
= 546

3 u + 6 u + 4 u = 546
13 u = 546

1 u = 546 ÷ 13 = 42

Total number of mini cupcakes sold by Class B and Class D
= 3 u + 4 u
= 7 u
= 7 x 42
= 294

Answer(s): 294